1. Field of the Invention
This invention generally relates to cutting inserts, especially metal cutting inserts with chip control that effectively break thin, foil-like chips that result from cutting of a workpiece.
2. Description of Prior Art
Cutting tools typically employ a replaceable cutting insert that is securely and accurately held in place on the cutting tool. The inserts are preferably intended for indexing so that a new cutting edge can be presented for removing metal from a workpiece once the cutting edge becomes dull or worn.
During the cutting operation, the edge engages the workpiece and creates a gap between the cut portion and the remainder of the workpiece. A chip starts to flow but remains intact with the workpiece until it engages a face of the tool, typically a face of the toolholder, which imparts a curl to the chip. During a third phase of the cutting operation the ribbon, or curl, is broken into pieces to facilitate removal from the cutting region.
Thus, the cutting operation generates a ribbon-like strip of material, usually metal, removed from the workpiece. It is important to control removal of the chip material so that it does not interfere with continued cutting operations. A great deal of time, effort, and design are associated with chip handling. Although chip breaking structures are well known in the art, there is a continuous need for improvement in the area. The insert must be able to effectively embrittle and repeatedly break the thin, foil-like chips over a wide range of chip thicknesses so that the cutting tools employing such inserts can operate effectively. In addition, the chip breaking structure should be capable of use in a wide range of insert shapes and sizes. Exemplary cutting arrangements exhibiting chip control are shown and described in U.S. Pat. Nos. 5,704,737 and 5,791,833, commonly assigned to the assignee of the present invention.